Space debris on Earth’s Orbit
Space junk, space debris, space waste — call it what you want, but just as junk and waste cause problems here on Earth, in space spent booster stages, nuts and bolts from ISS construction, various accidental discards such as spacesuit gloves and cameras, and fragments from exploded spacecraft could turn into a serious problem for the future of spaceflight if actions to mitigate the threat are not taken now. The European Space Operations Centre has put together some startling images highlighting this issue. Above is a depiction of the trackable objects in orbit around Earth in low Earth orbit (LEO–the fuzzy cloud around Earth), geostationary Earth orbit (GEO — farther out, approximately 35,786 km (22,240 miles) above Earth) and all points in between.
Between the launch of Sputnik on 4 October 1957 and 1 January 2008, approximately 4600 launches have placed some 6000 satellites into orbit; about 400 are now travelling beyond Earth on interplanetary trajectories, but of the remaining 5600 only about 800 satellites are operational – roughly 45 percent of these are both in LEO and GEO. Space debris comprise the ever-increasing amount of inactive space hardware in orbit around the Earth as well as fragments of spacecraft that have broken up, exploded or otherwise become abandoned. About 50 percent of all trackable objects are due to in-orbit explosion events (about 200) or collision events (less than 10).